stake



(Model.)

E. T. STARR. Dent-a1 Engine Hand Piece.

No. 231,734 Patented Ag. 31,1880.

WITNESSES UNITED 'STATES l PATENT Ormea.

ELI T. STARR, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T()Y JAMES W.WHITE, J. CLARENCE WHITE, AND H. M. LEVIS, ALL OF SAME PLAGE, ASTRUSTEES UNDER THE VILL OF SAMUEL S. WHITE, DEGEASED.

DENTAL-ENGINE HAND-PIECE.

SPECIFICATION forming part of Letters Patent No. 231,734, dated August31, 1880.

` Appncmion filed July 10,1880. (Model.)

To all whom t may concer-n:

Be it known that I, ELI T. STARR, a citizen of the United States,residing in the city and county of Philadelphia, in the State ofPennsylvania, have invented certain new and useful Improvements inDental-Engine Hand- Pieces, of which the following is a specification.

My invention relates to the class of hand- Io pieces for dental enginesin which the operating-tool is secured in the socket of they spindletool-holder or chuck by means of aspring-jaw or split tool-fasteningcarried by the chuck in its revolutions.

The best hantl'pieces of this type known to me are those exemplied inthe Letters Patent granted to Re Qua, January 22, 1878, as i No.199,469; Cushing, August 5, 1879, as No. 218,239, and Phillips,September 23, 1879, as No. 219,873.

My invention constitutes an improvement more especially upon thehand-pieces of Gushing and of Phillips, and has for its object theproduction of a superior instrument.

My invention consists in certain new coinbinations and organizations ofdevices, which are recited at the end of the specication.

In the accompanying drawings, whichillustrate the best way now known tome of embodying my improvements, Figure 1 is a longitudinal centralsection through the handpiece. Fig. 2 is a similar.- section through aportionof the hand-piece with some ot' the parts in positions differentfrom that depicted in Fig. 1. Fig. 3 is a transverse section through thedevice on the line 3 3 of Fig. 2, and Figs. 4 and 5 are similartransverse sections on the lines 4 4 and 5 5, respectively, of Fig. 1.

The casing A of the hai'id-piece is preferably composed of four tubularsectionsthat is, of a nose or end section, c, preferably of hardenedsteel 5 of a handle-section, a', which surrounds the tool-holder orchuck B and forms a sheath for it., said section being grasped usu- 4 5ally between the fm gers and thumb somewhat in the manner of holding apen or pencil, to guide the operatin g-tool and hold it toits work of asection, a2, preferably of hard metal, to which the handle section isconnected by screw-threads, so as to permit said handle-scc- 5o tion tobe readily detached to uncover the toolholder or chuck for oilin g, e.,and of a shank,- section, a3, connected with the said section a2 byscrew-threads, so as to permit ready separation of said sections inorder to obtain ac- 55 cess to the interior of the hand-piece.

The t0ol-holder or chuck B has its bearin gs at front in the nose orsection a of the casing and in rea-r of the hard-metal section c2, andis given a rapid revolving motion upon its lon- 6o gitudinal axis insaid tubular bearings by a flexible power-conveyer or shaft of the usualor any approved construction.

The shank-section a3 of the casing is preferably connected with theouter or free end of' 65 a flexible sheath or tube, which envelops theflexible power-conveyer to protect it-for eX- ainple, as in thewell-known. S.. S. White dental engine, and as shown in the reissuedLetters Patent granted to N. Stow, March 4, 1879. 7o

I have deemed it unnecessary to show either 'the flexible driving-shaft`or its exibleenveloping-sheath, as they frm no part of thesubject-matter herein'claimed.

The tool-holder is locked from endwise move- 7 5 1n ent in the casing byannular shoulders, which abut against corresponding shoulders formed onthe interior of the casing. The annular shoulder I) at the front end ofthe tool-holder constitutes the pull-bearing, preventing end- 8o wisemovement of said tool-holder in an outward direction when a pulling ordraw cut is being made with the operating-tool; and the annular shoulderb', formed by the milled collar b2, near the rear end of thetool-holder, 5 constitutes the push or thrust bearing, preventingendwise movement of the tool-holder in an inward direction when apressure or thrust cut is being made with the tool. l

The tool-holder or chuck is tubular. A 9o shaft, C, is passed throughthe chuck from end to end, the front end of which shaft is longitudinally split, so as to` form spring clampingjaws, and is socketedfor the insertion of the shanks of the operatingtools, which are clampedor fastened in the socket by the compression of the clamping-jaws.

The ends of the members of the split or spring-jawed tool-fasteningprotrude a short distance in front of the end of the chuck and terminatein a sli ghtly-enlarged tapering head, so that when drawn within themouth ofthe toolholder the said members will be closed together orcompressed, while when moved out from said mouth they will spring apart,eX- pand, or move laterally, as is common in this form oftool-fastening, and as fully described in the patents hereinbeforereferred to.

In order to positively move the said shaft C endwisc within thetool-holder or chuck to compress or release the clamping-jaws, (thetoolholder being locked from endwise movement, as before described,) thesaid shaft at its rear end, which is extended through and beyond therear end of the chuck, is provided wit-l1 a cl;1p-piece,D,itted upon theshaft and locked from endwise movement thereon by two collars, d d',fixed to the shaft, thefrontenlarged end ofsaid cup-piece beinginternally threaded to receive the externally or male threaded buttendof the chuck, so that by turning said chuck on its axis to screw it inor out of said cup, said cup, and with it the shaft C, will be caused tomove endwise to clamp or release the tool-fastening, according to thedirection of rotation of the chuck.

In order to prevent the said cup-piece from turning when it is desiredto operate the toolfastening, while permitting ,it to move end wise withsaid fastening as the chuck is turned by the milled collar b2, which isgrasped by the fingers through openings c c in the opposite sides of thecasing when the thimble or sleeve E is drawn back to expose saidopenings and collar, a pin or screw, j', is passed through said sleeve,and its end engages with one ot a series of i longitudinal peripheralgrooves, d2, formed on the cup-piece l). (Clearly shown in Figs. l, 2,and 3.)

The sleeve E is permitted to be moved backward and forward on the casingto en gage and disengage its screw ffrom the cup-piece by means of alongitudinal slot, g, in the easingseetions a2 a3, while it is preventedfrom turning relatively to said easing by said screw, wherebyit isobvious that it'the sleeve is drawn back to engage its screw with one ofthe grooves ot' the cup-piece D said cup-piece will be locked fromrotation independently of the casing, while the chuck may be turned byits milled collar in order to reciprocate the cuppiece and shaft C inthe chuck.

In operation, ofcourse the sleeve will be in its forward position, asshown in Fig. 1, to cover the openings c o', and so as not to in#terfere with the rotation of the shaft and chuck in the casing indriving the operating-tool.

Fig. 2 shows the sleeve E as drawn back, with its screw locking thecup-piece D from turning, to permit the milled collar b2 to be turned toscrew the cup-piece and shaft forward to release the tool-fastenin g.

The socket of the tool-fastenin g is preferably provided with atangential pin, h, or with a suitable lug to engage a notch in thetoolshank, so as to lock said tool firmly in the socket and enable it tobe driven firmly and positively without relying upon the tool-clampingdevices alone for the purpose.

It will be noticed that a chamber, z', is formed at the nose of thehand-piece forward of the front end of the tool-holder, and this is forthe purpose of arrestin g the entrance of extraneous matter to thebearing ot' the chuck, and for preventin g the escape of lubricating-oilto the outside ofthe hand-piece. This featureis the invention ofPhillips, whose patent has been above referred to.

I claim as my inventionl. The combination, substantially as hereinbeforeset forth, of the oasin g, the tubular toolholder turning in bearingstherein, the shaft passing through said tool-holder and having its frontend split to form tool-locking jaws, the cup-piece itted on said shaftso as to be incapable of endwise movement thereon and connected with thetool-holder by a screw-connect-ion, and the sliding thimble to look saidcup-piece from turning without preventing its endwise movement whileexposing the cluck for operation to enable theJ toollocking shaft 1 tobe reciproeated.

2. The combination, substantially as hereinbefore set forth, ot' thecasing having openings ill its side, the tubular chuck mounted in saidcasing and having a collar to turn it opposite said openin gs, the shaftextended through said chuck having a socket and clamping-jaws at itsfront end, the pin or lug in the socket of said chuck to enga-ge thelocking-notch of a tool-shank, the cup-piece on said shaft connectedwith the chuck by a screw-connection, and the sliding thimble whichlocks said cuppiece from turning while exposing the collar by whichthe'ehuck is turned to reciproca-te the In testimony whereof I havehereunto subscribed lny name.

ELI T. STARR. Witnessesz GEORGE P. MORGAN, WILLIAM H. GILBERT.

IOS

